Description of problem:
There is no way to filter the even display down to a specific time range)
Pre GWT this was possible via the global metric range settings.
I don't think that re-introducing the global metric range setting is right here,
but it should be possible to filter like on the Recent Operations/Recent Alerts reports with a start or end date. If none are given, the default (as is) should be taken.

Initial implementation is in master 82877c7c61a21cc22
The picker could probably be improved to allow to select the time as well.
The new class DateTimeFilterItem probably needs some love too.
Also the whole events history tab could be passed by some UXD expert.

The UI could be cleaned up as the default time widget created by smartGWT is very simplistic. Heiko had found a better looking widget:
http://sgwidgets.googlecode.com/svn/trunk/sgwidgets-demo/1.0.0/index.html
However, it is not i18n compatible. So while it would be easy to add this widget; making it i18n for the various timezone formats (and Daylight Savings Time issues) and languages is quite a daunting task.
To summarize: making it look pretty is easy, make it work internationally is very difficult.